package com.binc.testspring.util;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

public class AESUtils {

    // 加密
    public static String encrypts(String content, String key) {
        return parseByte2HexStr(encrypt(content, key));
    }

    // 解密
    public static String decrypts(String content, String key) {
        return new String(decrypt(parseHexStr2Byte(content), key));
    }

    /**
     * AES加密字符串
     *
     * @param content 需要被加密的字符串
     * @param key     加密需要的key
     * @return 密文
     */
    public static byte[] encrypt(String content, String key) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");// 创建AES的Key生产者
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            random.setSeed(key.getBytes());
            kgen.init(128, random);
            //加密没关系，SecureRandom是生成安全随机数序列，password.getBytes()是种子，只要种子相同，序列就一样，所以解密只要有password就行
            SecretKey secretKey = kgen.generateKey();// 根据用户密码，生成一个密钥
            byte[] enCodeFormat = secretKey.getEncoded();// 返回基本编码格式的密钥，如果此密钥不支持编码，则返回
            SecretKeySpec keySpec = new SecretKeySpec(enCodeFormat, "AES");// 转换为AES专用密钥
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = content.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, keySpec);// 初始化为加密模式的密码器
            byte[] result = cipher.doFinal(byteContent);// 加密
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }


    /**
     * 解密AES加密过的字符串
     *
     * @param content AES加密过过的内容
     * @param key     加密时的密码
     * @return 明文
     */
    public static byte[] decrypt(byte[] content, String key) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");// 创建AES的Key生产者
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            random.setSeed(key.getBytes());
            kgen.init(128, random);
            SecretKey secretKey = kgen.generateKey();// 根据用户密码，生成一个密钥
            byte[] enCodeFormat = secretKey.getEncoded();// 返回基本编码格式的密钥
            SecretKeySpec keySpec = new SecretKeySpec(enCodeFormat, "AES");// 转换为AES专用密钥
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, keySpec);// 初始化为解密模式的密码器
            byte[] result = cipher.doFinal(content);
            return result; // 明文   
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     *
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     *
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static void main(String[] args) {


        String content = "grfc1011";
//    	String key = "Ef5CiHQTZHgwHTX3LRuh5eHnwyCaiJta";
        String key = "yjyz_test";
        byte[] data = encrypt(content, key);
        String str = parseByte2HexStr(data);
        System.out.println(str);

        byte[] a = parseHexStr2Byte(str);
        byte[] dec = decrypt(a, key);
        System.out.println(new String(dec));
    }


}
